1. Field of the Invention
This invention relates to an apparatus and method for adjusting the spacing between characters in a printed character string in a computerized typesetting system, phototypesetting machine or word processor, etc., so as to make the character string easier to read and more attractive.
In this specification, the meaning of the term "character" covers all types of letters, symbols, signs, numerals and figures used to express will, thoughts and emotions, etc. Typical characters include Chinese characters (inclusive of Chinese numerals), hiragana and katakana in the Japanese language, the Hangul alphabet, the Roman alphabet, Greek letters, Arabian numerals, Roman numerals, hyphens, commas and colons, etc.
2. Description of the Prior Art
The adjustment of character spacing in a character string arrayed in the horizontal or vertical direction is one important operation in typesetting for printing purposes. In text which contains Chinese characters (hereinafter referred to as kanji), hiragana and katakana, especially headlines and advertisements appearing in leaflets, the impression which these characters have upon the reader is extremely important. This makes it necessary to perform kerning (adjustment of character spacing) in appropriate fashion.
A character spacing adjustment conventionally is carried out by a skilled operator. If the individual performing the operation does not possess sufficient experience, the operation cannot be carried out and the efficiency thereof declines.
An example of an apparatus that automates character spacing adjustment is proposed in the specification of Japanese Patent Application Laid-Open (KOKAI) No. 3-244542. According to the proposed art, an imaginary region (zone) of a fixed width is set along the outline of each character on the outer side thereof. The spacing between two adjacent characters is decided in such a manner that parts of the outer edges of the imaginary zones will contact each other. Alternatively, character spacing is adjusted in such a manner that the area of overlap between two adjacent imaginary zones maintains a fixed value.
With this automatic adjustment of character spacing, however, the spacing between characters is adjusted in dependence solely upon the outlines of the characters; other essential elements of the characters are not taken into consideration. For example, the broadness of the area of character faces, complexity and relationship between neighboring characters are not taken into account even though these are important factors that have an influence upon character spacing.